Haha this thread is hillarious.
I don't see how your save files could all be messed up...
....
I agree.. Small recap.
-AArgh quest messed up alllll my saves.. I am going to make a statement I want my money back. (see how I can abbreviate a single post in euphemistic manner)
-Reaction: Surely OP must be exaggerating. Counter arguments mostly about tone of voice.
-Derailment: OP could give a balanced reply, stating why he is angry... but nooo... starts calling people names.
-Suddenly someone actually tries to help.. (no reaction)
-Nobody really goes into his tips let alone OP.
-More bickering
In short: OP has a problem with a known Quest Bug. Said bug is apparently influencing all of his other saves. A fact which from an objective pov is extremely unlikely unless there are other issues at stake.
So short word of advice: Follow up the advice metajako gave you. The issue you describe might actually be more of a technical XBox problem than only be attributed towards a bugged quest.
To point out some other elements:
-OP's tone of voice is the entire problem with the thread.
-Uriel Nocturnes reply might be harsh but is mostly aimed at the manner in which OP adresses the issue.
-OP then reacts by namecalling.. which is always going to win arguments (not)
-Others come in the fray, claiming that people who post counter arguments to unfocussed anger are (lose translation) a bunch of Bethesda lovers.. Yes that's also going to help a healthy discussion (not)
-Suggesting OP has a modded X-Box or posting useless information like "I never had problems with this quest" are further derailing this thread.
Concluding: OP answer the questions asked by metjako and test other games. most likely your X-Box has a GPU problem or a caching issue. The quest in question can (!!) indeed be bugged.. So if you want a refund, be our guest and visit your retailer. To all others: A little discipline ... please.. (although it is an amusing read)